A man held as part of the investigation into the murder of a security guard in Mayfair on New Year's Day is the son of the banned radical cleric Abu Hamza.
Imran Mostafa Kamel is accused of possessing a firearm in relation to an incident at Fountain House, Park Lane, which happened soon after the killing.
Tudor Simionov, 33, was providing security for a party at a flat there.
Mr Kamel, 26, of The Grove, Ealing, appeared earlier at Westminster Magistrates' Court.
He has been charged with possession of a firearm with intent to cause fear or danger, and possession of a firearm when prohibited for life.
The Met Police said the charges related to an incident at Fountain House at about 05:35 GMT in which no firearm was discharged.
The force added the alleged offences were not linked to Mr Simionov's stabbing - which happened at about 05:30 - or the stabbing of three other people at the event.
Those three people, two men and a woman, did not receive life-threatening injuries.